Plagiorchis muris infection in Apodemus agrarius from northern Gyeonggi-do (Province) near the demilitarized zone

The small intestines of 6 species of rodents and 1 species of insectivore were examined seasonally for Plagiorchis muris infection in 3 different localities in northern Gyeonggi-do (Province), near the demilitarized zone (DMZ). A total of 1,496 animals, including 1,366 Apodemus agrarius, 54 Crocidura lasiura (insectivore), 32 Mus musculus, 28 Micronytus fortis, 9 Eothenomys regulus, 6 Micronys minutus, and 3 Cricetulus triton, were live-trapped at Yeoncheon-gun (n = 351), Paju-shi (804) and Pocheon-gun (343) at 3-mo intervals from December 2004 to September 2005. A total of 1,647 P. muris were collected from 72 (5.3%) A. agrarius. The infection rate was the highest in Pocheon-gun (8.2%), followed by Yeoncheon-gun (5.0%) and Paju-shi (4.2%). A higher infection rate was observed in A. agrarius captured during September (19.4%) than those captured during December (3.0%), June (2.6%), or April (0%). However, the worm burden was the highest in June (av. 32.1/animal), followed by September (24.7), December (4.0), and April (0). None of the other animal species were found infected with P. muris. The results reveal that A. agrarius is a natural definitive host for P. muris, and infection rates and worm burdens vary seasonally and geographically.     

Trypanosoma (Herpetosoma) grosi: first isolation from Chinese striped field mouse (Apodemus agrarius)

A "lewisi-like" Trypanosoma parasite was isolated from the blood of Chinese striped field mice (Apodemus agrarius) trapped in the fields in the Gannan Tibet area, Gansu province, China. The parasite was successfully cultivated in vitro in HL-1 medium supplemented 20% fetal bovine serum (FBS). Full formed spheromastigote, metacyclic trypomastigote and trypomastigote structures were all visible in films made from the culture. A nucleotide fragment of 2159-bp length was amplified from genomic DNA of the parasite using specific primers for the 18S rRNA gene of trypanosomes. The alignment indicated that this parasite had higher identities with T. (Herpetosoma) grosi (more than 99.6%) than other Herpetosoma species (less than 98.5%), which suggest that the parasite should be classified as T. (Herpetosoma) grosi. This is the first time in China that an isolation of T. (Herpetosoma) grosi is reported although several strains of T. (Herpetosoma) lewisi have been isolated from rodents of family Muridae in various provinces. Thus, it was designated as T. (Herpetosoma) grosi Cha1 and deposited in the center of parasite strain collection and preservation in our laboratory for future study. In addition, this culture method will be used to isolate, maintain and study the long-term development of this parasite in vitro.     

无前恙螨属--新种记述(蜱螨目:恙螨科)

本描述了采自江苏马铁菊头蝠(Rhinolophus ferrum-eguinum)翅上的无前恙螨属一新种,即宜兴无前恙螨[Walchia(Walchia)neeshini Wang et Xia,sp．nov]。模式标本保存于复旦大学上海医学院寄生虫学教研室。     

贵州地区黑线姬鼠种群繁殖特征

黑线姬鼠(Apodemus agrarius)是贵州地区分布广泛的主要农田害鼠之一,掌握其种群繁殖特征可为种群动态的预测预报提供基础资料。1984~2014年间,采用夹夜法逐月调查了贵州省余庆县8个县(市)监测点黑线姬鼠种群动态数据,分析了其种群性比、雌鼠怀孕率和平均胎仔数、雄鼠睾丸下降率等主要繁殖生物学指标及其地理差异和季节性变动规律,明确了贵州地区黑线姬鼠种群的繁殖特征。共捕获黑线姬鼠20 113只,不同地区种群间,除平均胎仔数有显著差异外(χ~2=36.503,df=7,P0.01),其他繁殖特征值均没有差异。从时间序列看,种群中雌鼠怀孕率和雄鼠睾丸下降率的季节性变化均表现为春季(4~5月)及夏末秋初(8~9月)达到高峰的双峰型。雌鼠产仔数一般2~10只,4~7只最为常见(占93.87%)。不同季节平均胎仔数差异不大。贵州地区黑线姬鼠繁殖的总体特点为全年繁殖,春秋两季为繁殖的高峰期,冬季(12月份和翌年1、2月份)繁殖强度明显低于其他季节(F_(11,84)=61.92,P0.01),但种群密度表现为6月达到最高点的单峰型特点。     

Stylostome formation in trombiculid mites (Acariformes: Trombiculidae)

Stylostomes of the trombiculid mite larvae Neotrombicula pomeranzevi (Schluger), Hirsutiella zachvatkini (Schluger), Miyatrombicula esoensis (Sasa and Ogata) and Euschoengastia rotundata (Schluger) (Acariformes: Trombiculidae), formed in the host skin during feeding of the parasites on their natural hosts (voles) were studied histologically and histochemically. A stylostome is a variously shaped tube formed of solidified mite saliva that extends from the mouthparts of the parasite through the epidermis into the dermis of the host, and allows the mite to obtain its liquid food. The first step of stylostome formation is deposition of an eosinophilic cone, to which the larva’s chelicerae are glued. Organization of the stylostome depends on the mite species, and its walls may show weakly expressed longitudinal or transverse stratification. Histochemically, the stylostome is composed of complex glycoprotein with varying tinctorial properties through the width or the length of the stylostome’s walls. Beneath the distal end of the stylostome, irrespectively of its localization either in the epidermis or in the dermis of the host, a feeding cavity is formed as a result of the action of the hydrolytic components of the mite’s saliva forced through the stylostome into the wound. An inflammatory dermal reaction of moderate intensity is evolved during larval feeding and stylostome formation. It is manifested by the infiltration of the foci with neutrophiles, lymphocytes and macrophages and by dilation of capillaries of the terminal vessel bed and filling them by erythrocytes and other blood elements. Around the stylostome, necrosis of the epidermal cells occurs, leucocytes come to the damaged area and fuse with the necrotic epidermal cells, leading to the formation of the large scabs on the surface of the host’s skin. In the case of E. rotundata, single capsules having a terminal opening and containing feeding larva are formed on the abdomen of the hosts. The walls of the capsules are composed of the mite’s saliva flowing upon the surface of the host’s skin. At the bottom of the capsule, a stylostome perforating the epidermis is also present.